Antimicrobial hydrogel dressings

Abstract

Antimicrobial dressings effective for treating biofilms in wounds are provided. One embodiment provides a wound dressing containing a silver-releasing conformable substrate and hydrogel containing a therapeutic substance. The hydrogel layer optionally may contain a pattern and/or one or more apertures, and may be secured by an optional non-adherent netting. A preferred substrate is a silver-coated substrate, for example silver-coated nylon. The silver-coated nylon can be a knitted, woven, compound, or complex fabric. Silver fibers can be combined within non-woven fabrics. The silver containing substrate, can be non-adherent and/or may contain one or more apertures, and/or may contain elastane. The dressing optionally contains one or more of: an adhesive layer, a separation layer, a moisture regulation layer, a film layer, and combinations thereof.

1 . A wound dressing comprising:
 at least one conformable layer comprising:   yarns or fibers containing multiple filaments of nylon, wherein at least the majority of yams or fibers are completely and circumferentially coated with metallic silver by an electroless silver plating process, where at least one side of the conformable layer is at least partially coated with hydrogel or adjoined by a hydrogel layer comprising a therapeutic substance or substances or their derivatives, optionally a surfactant or surfactants, and has a pH of approximately 2-7, inhibits or reduces biofilm formation, and   wherein the wound dressing releases at least about 5 ppm of ionic silver within 24 hours into a wound or wound fluids when in contact with the wound or wound fluids.   
     
     
         2 . The wound dressing of  claim 1 , wherein the therapeutic substance or substances comprises hyaluronic acid, hypochlorous acid, ascorbic acid, acrylic acid, algenic acid, boric acid, citric acid, or acetic acid, cleansers, coagulants, growth factors, surfactants, moisturizers, antimicrobials, or derivatives and/or combinations thereof 
     
     
         3 . The wound dressing of  claim 1 , wherein the hydrogel has a thickness of about 2-20 mm, and optionally may be secured by open netting or film. 
     
     
         4 . The wound dressing of  claim 1 , further comprising a moisture regulation layer for absorbing or donating moisture, and optionally contains silver-coated fibers. 
     
     
         5 . The wound dressing of  claim 1 , optionally containing a film top layer above the moisture regulation layer or hydrogel. 
     
     
         6 . The wound dressing of  claim 1 , optionally containing one or more permeable or porous separation layer(s) between any or all dressing layers. 
     
     
         7 . The wound dressing of  claim 1 , wherein the moisture regulation layer comprises a foam, a sponge or sponge-like material, cellulosic materials, cotton, rayon, polyvinyl alcohol, polyvinyl acetate, polyethylene oxide, polyvinyl pyrrolidone, polyurethane hydrocolloids, alginates, hydrogels, hydrocolloids, hydrofibrils, collagens or any combinations thereof. 
     
     
         8 . The wound dressing of  claim 1 , wherein the conformable layer contains elastane. 
     
     
         9 . The wound dressing of  claim 1 , wherein the dressing comprises-two layers of conformable substrate separated by a hydrogel, and,
 wherein dressing optionally contains separation layers between any and all layers.   
     
     
         10 . An island dressing, comprising:
 a conformable layer comprising:   yams or fibers containing multiple filaments of nylon, wherein at least a majority of the yarns or fibers are completely and circumferentially coated with metallic silver by an electroless silver plating process, and   wherein the conformable layer optionally comprises elastane, and &   wherein at least one side of the conformable layer is at least partially coated with hydrogel comprising a therapeutic substance of  claim 2  and has a pH of approximately 2-7, and inhibits or reduces biofilm formation, and   a moisture regulation layer on top of either the comfortable layer or hydrogel layer, and   an adhesive layer covering the moisture regulation layer,   wherein the island dressing releases at least about 5 ppm of ionic silver within 24 hours into a wound or wound fluids when in contact with the wound or wound fluids.   
     
     
         11 . The island dressing of  claim 10 , further comprising one or more separation layers separating the hydrogel from either the conformable layer and/or the moisture regulation layer. 
     
     
         12 . The island dressing of  claim 10 , further comprising a film layer between the adhesive and moisture regulation layer. 
     
     
         13 . A pad dressing comprising:
 a conformable layer comprising:   yams or fibers containing multiple filaments of nylon, wherein at least a majority of the yarns or fibers are completely and circumferentially coated with metallic silver by an electroless silver plating process,   a hydrogel on top of or below the conformable layer, wherein the hydrogel comprises a therapeutic substance of  claim 2  and has a pH of approximately 2-7, inhibits or reduces biofilm formation, and a moisture regulation layer on top of the hydrogel or the conformable layer,   wherein the pad dressing releases at least about 5 ppm of ionic silver within 24 hours into a wound or wound fluids when in contact with the wound or wound fluids.   
     
     
         14 . A pad dressing of  claim 13 , further comprising one or more separation layer(s) between the hydrogel and either the conformable layer and/or the moisture regulation layer. 
     
     
         15 . A dressing of  claim 13 , further comprising a film layer covering the moisture regulation layer. 
     
     
         16 . A dressing of  claim 13 , wherein the conformable layer contains elastane. 
     
     
         17 - 20 . (canceled) 
     
     
         21 . The dressing of  claim 1 , further comprising a securing netting securing the hydrogel to the conformable layer. 
     
     
         22 . The wound dressing of  claim 1 , wherein the amount of ionic silver is determined using Test 1. 
     
     
         23 . The wound dressing of  claim 1 , wherein the amount of ionic silver is determined using Test 2.